This invention relates to the field of exercise machines, and specifically to a simplified heart rate calculator which permits the user of an exercise machine (operator) to determine his/her current heart rate, in order to judge the aerobic progress of the exercise.
One of the primary goals of aerobic exercising is to permit the user to obtain a temporary heart rate increase. This is considered desirable as a method of improving physical fitness. However, it is not desirable to drive the heart rate to an excessive level.
Exercise machines often incorporate heart rate monitors, which permit the user to learn his/her current heart rate during the exercise regimen. Heretofore, the devices used have been designed to engage the body of the user in a location where a pulse is available, such as the wrist or neck. The device counts the pulses and calculates the pulse rate, which is available for display.
The most common practice is a crude approach, in which the user leaves the exercise machine, and then counts his/her pulse while looking at a nearby clock or watch. The general practice is either to count the pulse for 15 seconds and then multiply the count by 4, or to count for 30 seconds and multiply by two.
Either of the two heart rate determining techniques just discussed has significant limitations. The counting and calculating by the user is not very accurate because of the need both to synchronize the pulse counting with the observed clock or watch, and to make the correct calculation. It also requires taking a count over a relatively long period if reasonable accuracy is desired.
The heart rate monitors which engage the body to automatically count the pulses have not been very satisfactory. Under the conditions of normal aerobic exercising, they have great difficulty in accurately sensing the heart beat. The ease or difficulty of sensing the heart beat varies from person to person. Some individuals have heart beats which are almost impossible to sense without the use of electrodes. Furthermore, the environment may cause interference which tends to cause sensor inaccuracy.